Rechercher une fonction PHP

array_map

(PHP 4 >= 4.0.6, PHP 5, PHP 7)

array_mapApplies the callback to the elements of the given arrays

Description

array_map ( callable $callback , array $array1 [, array $... ] ) : array

array_map() returns an array containing the results of applying the callback function to the corresponding index of array1 (and ... if more arrays are provided) used as arguments for the callback. The number of parameters that the callback function accepts should match the number of arrays passed to array_map().

PHP: array_map - Manual Home of Manuel PHP  Contents Haut

Parameters

callback

Callback function to run for each element in each array.

NULL can be passed as a value to callback to perform a zip operation on multiple arrays. If only array1 is provided, array_map() will return the input array.

array1

An array to run through the callback function.

...

Supplementary variable list of array arguments to run through the callback function.

PHP: array_map - Manual Home of Manuel PHP  Contents Haut

Return Values

Returns an array containing the results of applying the callback function to the corresponding index of array1 (and ... if more arrays are provided) used as arguments for the callback.

PHP: array_map - Manual Home of Manuel PHP  Contents Haut

Examples

Example #1 array_map() example

<?php
function cube($n)
{
    return (
$n $n $n);
}

$a = [12345];
$b array_map('cube'$a);
print_r($b);
?>

This makes $b have:

Array
(
    [0] => 1
    [1] => 8
    [2] => 27
    [3] => 64
    [4] => 125
)

Example #2 array_map() using a lambda function (as of PHP 5.3.0)

<?php
$func 
= function($value) {
    return 
$value 2;
};

print_r(array_map($funcrange(15)));
?>
Array
(
    [0] => 2
    [1] => 4
    [2] => 6
    [3] => 8
    [4] => 10
)

Example #3 array_map() - using more arrays

<?php
function show_Spanish($n$m)
{
    return 
"The number {$n} is called {$m} in Spanish";
}

function 
map_Spanish($n$m)
{
    return [
$n => $m];
}

$a = [12345];
$b = ['uno''dos''tres''cuatro''cinco'];

$c array_map('show_Spanish'$a$b);
print_r($c);

$d array_map('map_Spanish'$a $b);
print_r($d);
?>

The above example will output:

// printout of $c
Array
(
    [0] => The number 1 is called uno in Spanish
    [1] => The number 2 is called dos in Spanish
    [2] => The number 3 is called tres in Spanish
    [3] => The number 4 is called cuatro in Spanish
    [4] => The number 5 is called cinco in Spanish
)

// printout of $d
Array
(
    [0] => Array
        (
            [1] => uno
        )

    [1] => Array
        (
            [2] => dos
        )

    [2] => Array
        (
            [3] => tres
        )

    [3] => Array
        (
            [4] => cuatro
        )

    [4] => Array
        (
            [5] => cinco
        )

)

Usually when using two or more arrays, they should be of equal length because the callback function is applied in parallel to the corresponding elements. If the arrays are of unequal length, shorter ones will be extended with empty elements to match the length of the longest.

An interesting use of this function is to construct an array of arrays, which can be easily performed by using NULL as the name of the callback function

Example #4 Performing a zip operation of arrays

<?php
$a 
= [12345];
$b = ['one''two''three''four''five'];
$c = ['uno''dos''tres''cuatro''cinco'];

$d array_map(null$a$b$c);
print_r($d);
?>

The above example will output:

Array
(
    [0] => Array
        (
            [0] => 1
            [1] => one
            [2] => uno
        )

    [1] => Array
        (
            [0] => 2
            [1] => two
            [2] => dos
        )

    [2] => Array
        (
            [0] => 3
            [1] => three
            [2] => tres
        )

    [3] => Array
        (
            [0] => 4
            [1] => four
            [2] => cuatro
        )

    [4] => Array
        (
            [0] => 5
            [1] => five
            [2] => cinco
        )

)

The returned array will preserve the keys of the array argument if and only if exactly one array is passed. If more than one array is passed, the returned array will have sequential integer keys.

Example #5 NULL callback with only array1

<?php
$array 
= [123];
var_dump(array_map(null$array));
?>

The above example will output:

array(3) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  int(3)
}

Example #6 array_map() - with string keys

<?php
$arr 
= ['stringkey' => 'value'];
function 
cb1($a) {
    return [
$a];
}
function 
cb2($a$b) {
    return [
$a$b];
}
var_dump(array_map('cb1'$arr));
var_dump(array_map('cb2'$arr$arr));
var_dump(array_map(null,  $arr));
var_dump(array_map(null$arr$arr));
?>

The above example will output:

array(1) {
  ["stringkey"]=>
  array(1) {
    [0]=>
    string(5) "value"
  }
}
array(1) {
  [0]=>
  array(2) {
    [0]=>
    string(5) "value"
    [1]=>
    string(5) "value"
  }
}
array(1) {
  ["stringkey"]=>
  string(5) "value"
}
array(1) {
  [0]=>
  array(2) {
    [0]=>
    string(5) "value"
    [1]=>
    string(5) "value"
  }
}

PHP: array_map - Manual Home of Manuel PHP  Contents Haut

See Also

  • array_filter() - Filters elements of an array using a callback function
  • array_reduce() - Iteratively reduce the array to a single value using a callback function
  • array_walk() - Apply a user supplied function to every member of an array
  • information about the callback type

Find a PHP function

English translation

You have asked to visit this site in English. For now, only the interface is translated, but not all the content yet.

If you want to help me in translations, your contribution is welcome. All you need to do is register on the site, and send me a message asking me to add you to the group of translators, which will give you the opportunity to translate the pages you want. A link at the bottom of each translated page indicates that you are the translator, and has a link to your profile.

Thank you in advance.

Document created the 30/01/2003, last modified the 26/10/2018
Source of the printed document:https://www.gaudry.be/en/php-rf-array-map.html

The infobrol is a personal site whose content is my sole responsibility. The text is available under CreativeCommons license (BY-NC-SA). More info on the terms of use and the author.

References

  1. View the html document Language of the document:fr Manuel PHP : http://php.net

These references and links indicate documents consulted during the writing of this page, or which may provide additional information, but the authors of these sources can not be held responsible for the content of this page.
The author This site is solely responsible for the way in which the various concepts, and the freedoms that are taken with the reference works, are presented here. Remember that you must cross multiple source information to reduce the risk of errors.

Contents Haut